JPH08160320A - Endoscope device - Google Patents

Abstract

(57) [Summary] [Object] To provide an endoscope apparatus capable of efficiently diffusing and emitting illumination light without increasing the diameter of the distal end portion of the endoscope. An illumination fiber bundle 11 provided in an endoscope scope for supplying illumination light to a distal end portion of the endoscope scope, and an illumination fiber bundle in close contact with a light emission surface of the illumination fiber bundle are provided. And a cone-shaped rod 13 made of a truncated cone-shaped optical fiber having a light emitting end diameter smaller than the end diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope device used for medical and industrial purposes, and more particularly to a technique for illuminating a subject.

[0002]

2. Description of the Related Art Conventionally, there have been known medical endoscopic devices used for diagnosing the inside of a body cavity and industrial endoscopic devices used for observing positions that cannot be visually confirmed. Figure 5
Fig. 1 shows a typical external view of a medical endoscope device. As shown in FIG. 5, the endoscope apparatus 100 includes an operation section 101 for operating the endoscope, an insertion section 103 to be inserted into a body cavity, and an endoscope scope 107 including a tip section 105 having an optical system such as a lens. And an endoscope body 109 that performs image processing of image pickup data obtained by the endoscope scope 107.

Further, since the endoscope apparatus 100 needs to illuminate the diagnosis site in the body cavity, it has a light source in the endoscope body 109. The light emitted from this light source is provided in the endoscope scope 107 with a heat ray reflection filter provided in the endoscope body 109 for reflecting heat rays, a light quantity adjusting diaphragm for adjusting the light quantity, a condenser lens for collecting the light, and the endoscope scope 107. The distal end portion 10 of the endoscope scope 107 via the illumination optical system described later.
It is emitted as illumination light from 5.

FIG. 6 shows a sectional view of the illumination optical system.
As shown in FIG. 5, the illumination optical system 110 includes an operation unit 101.
An illumination fiber bundle 111 that reaches the tip 105 through the insertion portion 103 and an illumination lens 113 provided at the tip 105. The illumination fiber bundle 111 is composed of a bundle of a plurality of optical fibers 111a as shown in FIG.

Here, the illumination light requires illumination within a certain range. Therefore, a diffusion lens, particularly a plano-concave lens, is often used as the illumination lens. Also, a fiber bundle for illumination is fixed by twisting it around its center axis, and the optical axis of each optical fiber is inclined with respect to the center axis of the fiber bundle for illumination to diffuse light. ing.

The angle of light incident on the optical fiber (deviation angle of light with respect to the optical axis, hereinafter referred to as incident angle) and the angle of light emitted from the optical fiber (deviation angle of light with respect to the optical axis,
The upper limit of the output angle will be limited by the refractive index of the core in the central part of the optical fiber and the cladding of the peripheral part, and is usually expressed by a physical quantity NA (numerical apertuer).

In the case of diffusing light by twisting the illumination fiber bundle, the output angle of light is larger than the incident angle, and the NA apparently behaves as if it were large. By combining a twisted fiber bundle for illumination with a diffusing lens, a wider range can be illuminated because the light is already diffused before being diffused by the diffusing lens.

[0008]

However, when a plano-concave lens is used as the diffusing lens, as shown in FIG. 8, the plano-concave lens 113 starts from near the center of the fiber bundle for illumination.
Rays R101 and R102 incident near the center of are refracted by the plano-concave lens 113 and r101 and r1.
The rays R103 and R104 which are emitted as 02 but are incident on the peripheral portion of the plano-concave lens 113 from the vicinity of the illumination fiber bundle are refracted by the plano-concave lens 113 and strike the side surface portion 113a of the plano-concave lens 113 to reach the plano-concave lens 113. Is not ejected from. For this reason,
There is a problem that not only the light cannot be diffused sufficiently, but also the plano-concave lens 113 loses the amount of light.

Further, in order to sufficiently diffuse light using a diffusing lens including a plano-concave lens, it is necessary to increase the diameter of the entrance surface of the diffusing lens, and the diameter of the tip portion of the endoscope is also large. There is a problem that it is necessary to do.

In the case of diffusing light by twisting the illuminating fiber bundle, the illuminating fiber bundle is twisted about its central axis and the optical axis of the optical fiber is tilted with respect to the central axis of the illuminating fiber bundle. However, there is a problem that it is difficult to control the inclination angle of each optical fiber to a desired value.

The present invention has been made in view of the above circumstances, and an object thereof is to efficiently diffuse and emit illumination light without increasing the diameter of the distal end portion of the endoscope. To provide a simple endoscope apparatus.

[0012]

In order to achieve the above object, the present invention provides an optical fiber for illumination, which is provided in an endoscope and supplies illumination light to a distal end portion of the endoscope. The optical path conversion means is provided so as to be in close contact with the light emitting surface of the optical fiber, and the optical path converting means includes a truncated conical optical fiber having a light emitting end diameter smaller than a light incident end diameter.

A diffusing lens is provided on the light exit side of the light path conversion means. Furthermore, an optical fiber for illumination which is provided in the endoscope and supplies illumination light to the distal end portion of the endoscope, and a concave surface is arranged toward the light emitting surface of the optical fiber, and the side surface is inclined. In addition, a plano-concave lens in which a highly reflective metal is vapor-deposited is provided on the side surface.

Further, there is provided a condenser lens which is arranged between the optical fiber and the plano-concave lens and whose focal point is at the same point as the center of curvature of the concave surface of the plano-concave lens or at a point slightly concave from the center of curvature. It is characterized by that.

Further, an optical fiber for illumination which is provided in the endoscope and supplies illumination light to the distal end portion of the endoscope and a light emitting surface of the optical fiber are closely attached to each other, and a light incident end is provided. A light path conversion means comprising a truncated cone-shaped optical fiber having a light emitting end diameter smaller than the diameter of the portion,
The concave surface is arranged toward the light emitting surface of the optical path conversion means,
It is characterized in that it has a plano-concave lens in which the side surface is inclined and the highly reflective metal is vapor-deposited on the side surface.

Further, the light is arranged between the optical path conversion means and the plano-concave lens, and the focal point is at the same point as the center of curvature of the concave surface of the plano-concave lens or at a point a little concave from the center of curvature. It is characterized by having a lens.

[0017]

According to the above construction, the optical fiber is provided inside the endoscope and supplies the illumination light to the distal end portion of the endoscope. The light path conversion means is provided in close contact with the light emitting surface of the optical fiber, and is composed of a truncated cone-shaped optical fiber having a light emitting end diameter smaller than the light incident end diameter, and the light supplied from the optical fiber is Diffuse and emit. Therefore, the illumination light can be efficiently diffused and emitted without increasing the diameter of the tip portion of the endoscope.

Further, the diffusing lens provided on the light exit side of the light path conversion means further diffuses the illumination light diffused by the light path conversion means. Further, the plano-concave lens has a concave surface arranged toward the light emitting surface of the optical fiber, has a side surface inclined, and has a highly reflective metal vapor-deposited on the side surface. The illumination light is efficiently diffused and emitted without increasing the size.

Further, the condenser lens is arranged between the optical fiber and the plano-concave lens, and the focal point is at the same point as the center of curvature of the concave surface of the plano-concave lens or at a point slightly concave from the center of curvature. The illumination light is condensed and then diffused.

[0020]

Embodiments of the endoscope apparatus according to the present invention will be described below with reference to the drawings. In addition, the endoscope apparatus according to the present invention,
The external appearance is the same as that of the endoscope device 100 shown in FIG. 5, and particularly relates to an illumination optical system provided in the endoscope scope 107.

FIG. 1 is a sectional view showing an illumination optical system of an endoscope apparatus which is a first embodiment of the endoscope apparatus according to the present invention. As shown in FIG. 1, the illumination optical system 10 of the endoscope apparatus according to the first embodiment is provided in close contact with an illumination fiber bundle 11 that is a bundle of optical fibers and a light emission surface of the illumination fiber bundle 11. The cone-shaped rod 13
It comprises a plano-concave lens 15 arranged on the light emitting side of the cone-shaped rod 13.

The illuminating fiber bundle 11 includes an operating section 101 and an inserting section 10 of the endoscope scope 107 shown in FIG.
3, a heat ray reflection filter for reflecting heat rays emitted from a light source provided in the endoscope body 109, a light quantity adjusting diaphragm for adjusting light quantity, and a condenser lens for collecting light. The illumination light that has passed through is incident on the cone-shaped rod 13.

The cone-shaped rod 13 is composed of a single truncated cone-shaped optical fiber sandwiched between two planes orthogonal to the optical axis. Further, as shown in FIG. 2, it is divided into a core 17 in the central portion and a clad 19 in the peripheral portion. Furthermore, core 1
7 is made of a material having a larger refractive index than the clad 19. Further, the incident surface 21 of the cone-shaped rod 13
Has the same shape as the light emitting surface of the illumination fiber bundle 11. Further, the side surface is inclined with respect to the optical axis so that the diameter of the exit surface 23 is smaller than the diameter of the entrance surface 21 of the cone-shaped rod 13.

The plano-concave lens 15 is arranged with its concave surface 15a facing the light emitting side of the cone-shaped rod 13, diffuses the light incident from the cone-shaped rod 13, and emits it as illumination light. Further, the concave surface 15a of the plano-concave lens 15 is slightly larger than the emitting surface 23 of the cone-shaped rod 13 because the light emitted from the cone-shaped rod 13 is diffused. Further, the plano-concave lens 15 is provided on the exit surface 2 of the cone-shaped rod 13.
3 and the peripheral surface of the concave surface 15a are arranged on the same plane or slightly on the emitting side of the emitting surface 23 of the cone-shaped rod 13.

The cone-shaped rod 13 and the plano-concave lens 1
5 are arranged so that their optical axes are on the same straight line as the optical axis of the illumination fiber bundle 11. Next, the optical characteristics of the cone-shaped rod 13 will be described with reference to FIG. The light ray R that has entered the incident surface 21 of the cone-shaped rod 13 is refracted by the incident surface 21 and enters the inside of the cone-shaped rod 13. The light ray R that has entered the cone-shaped rod 13 is repeatedly reflected at the boundary between the core 17 and the clad 19, and then refracted by the exit surface 23 of the cone-shaped rod 13 to be emitted as a ray r to the outside of the cone-shaped rod 13. It

The normal rod fiber (without inclination of the side surface) has the same incident angle and the same emission angle, but in the case of the cone-shaped rod 13, the boundary surface between the core 17 and the clad 19 is inclined with respect to the optical axis. Therefore, the output angle and the incident angle are not the same. As shown in FIG. 2, when the diameter of the entrance surface 21 is larger than the diameter of the exit surface 23, the exit angle is larger than the entrance angle.

As described above, since the illumination optical system 10 of the endoscope apparatus of the first embodiment is provided with the cone-shaped rod 13 in close contact with the light emitting surface of the illumination fiber bundle 11, the illumination fiber is provided. Light can be emitted at a larger emission angle than the light emitted from the bundle 11.

Therefore, it is possible to form light having a certain spread before it enters the plano-concave lens 15, and in cooperation with the diffusing action of the plano-concave lens 15, it is possible to realize wider diffusion of light.

The diffusion angle of the light emitted from the cone-shaped rod 13 can be controlled by the ratio of the diameter of the incident surface 21 of the cone-shaped rod 13 to the diameter of the emission surface 23 and the length of the cone-shaped rod 13. A desired diffusion angle can be selected by appropriately selecting the diameter of the entrance surface 21 and the diameter of the exit surface 23.

Further, the emitting surface 23 of the cone-shaped rod 13
Since the diameter of is smaller than the diameter of the light emitting surface of the illumination fiber bundle 11, the diameter of the plano-concave lens 15 can be made smaller than in the case where the cone-shaped rod 13 is not provided. Therefore, the distal end portion 105 of the endoscope scope 107 is
Also, the diameter can be reduced as compared with the case where the cone-shaped rod 13 is not provided.

FIG. 3 is a sectional view showing an illumination optical system of an endoscope apparatus which is a second embodiment of the endoscope apparatus according to the present invention. As shown in FIG. 3, the illumination optical system 30 of the endoscope apparatus according to the second embodiment includes an illumination fiber bundle 31 which is a bundle of optical fibers, and a cone arranged on the light emission side of the illumination fiber bundle 31. And a plano-concave lens 33.

The illuminating fiber bundle 31 includes an operating section 101 and an inserting section 10 of the endoscope scope 107 shown in FIG.
3, a heat ray reflection filter for reflecting heat rays emitted from a light source provided in the endoscope body 109, a light quantity adjusting diaphragm for adjusting light quantity, and a condenser lens for collecting light. The illumination light that has passed through is incident on the cone-shaped plano-concave lens 33.

The cone-shaped plano-concave lens 33 is arranged with its concave surface 33a facing the light emitting side of the illuminating fiber bundle 31, diffuses the light incident from the illuminating fiber bundle 31, and emits it as illumination light. Further, the cone-shaped plano-concave lens 33 has a side surface portion 35 provided with an inclination with respect to the optical axis. The inclination angle is set such that the light rays that are incident on the concave surface 33a from the illuminating fiber bundle 31 and are refracted and strike the inner surface of the side surface portion 35 are reflected substantially parallel to the optical axis of the illuminating fiber bundle 31. Further, the inner surface of the side surface portion 35 is vapor-deposited with a highly light-reflecting metal such as silver or aluminum.

The cone-shaped plano-concave lens 33 is arranged so that its optical axis is on the same straight line as the optical axis of the illumination fiber bundle 31. Next, the cone-shaped plano-concave lens 3
The optical characteristics of No. 3 will be described with reference to FIG. Here, among the light rays emitted from the illumination fiber bundle 31, the light rays R1 and R2 near the optical axis C and the light rays R3 and R near the peripheral portion of the illumination fiber bundle 31.
The four lines 4 will be described as a representative.

As shown in FIG. 3, the light rays R1 and R2 emitted from the illuminating fiber bundle 31 are incident on the concave surface 33a of the cone-shaped plano-concave lens 33, are refracted, and are emitted.
Light rays r1 and r2 are emitted from 3b.

On the other hand, the light rays R3 and R4 emitted from the illumination fiber bundle 31 are cone-shaped plano-concave lens 33.
The light enters the concave surface 33 a of the cone-shaped plano-concave lens 33 and is refracted to hit the inner surface of the side surface portion 35 of the cone-shaped plano-concave lens 33. Here, in the side surface portion 35 of the cone-shaped plano-concave lens 33, the light rays that are incident on the concave surface 33a from the illuminating fiber bundle 31 and are refracted and hit the inner surface of the side surface portion 35 are reflected substantially parallel to the optical axis of the illuminating fiber bundle 31. Inclined to do. Furthermore, the inner surface of the side surface portion 35 is vapor-deposited with a highly light-reflecting metal such as aluminum. Therefore, the light rays R3 and R4 are transmitted through the side surface portion 35.
Upon hitting the inner surface, the light is reflected substantially parallel to the optical axis of the illuminating fiber bundle 31, and is emitted as light rays r3 and r4 from the emitting surface 33b. Thereby, a light ray that has not been conventionally made an illumination light can be made an illumination light.

As described above, since the illumination optical system 30 of the endoscope apparatus of the second embodiment has the cone-shaped plano-concave lens 33 arranged on the light emitting side of the illumination fiber bundle 31,
Light rays emitted from the vicinity of the peripheral portion of the fiber bundle 31 for illumination, which has been a loss in the past, can also be used as illumination light.

Further, by selecting the cone-shaped plano-concave lens 33 having different inclination angles of the side surface portion 35, it becomes possible to change the emission angle of the light beam emitted from the cone-shaped plano-concave lens 33.

In the illuminating optical system 30 of the endoscope apparatus of the second embodiment, the cone-shaped plano-concave lens 33 is arranged on the light emitting side of the illuminating fiber bundle 31, but the first embodiment shown in FIG. Similar to the illumination optical system 10 of the endoscope apparatus of the embodiment, the cone-shaped rod 13 is provided so as to be in close contact with the light emission surface of the illumination fiber bundle 11, and the cone-shaped rod 13 is provided on the emission surface 23 side. You may make it arrange | position the cone-shaped plano-concave lens 33 shown in FIG. In this case, since the diameter of the emission surface 23 of the cone-shaped rod 13 is smaller than the diameter of the light emission surface of the illumination fiber bundle 31, the diameter of the cone-shaped plano-concave lens 33 is smaller than that when the cone-shaped rod 13 is not provided. can do. Therefore, the distal end portion 105 of the endoscope can also have a smaller diameter than in the case where the cone-shaped rod 13 is not provided.

FIG. 4 is a sectional view showing an illumination optical system of an endoscope apparatus which is a third embodiment of the endoscope apparatus according to the present invention. As shown in FIG. 4, the illumination optical system 40 of the endoscope apparatus according to the third embodiment includes an illumination fiber bundle 41 which is a bundle of optical fibers, and a light-collecting side arranged on the light emission side of the illumination fiber bundle 41. It is composed of a lens 43 and a cone-shaped plano-concave lens 45 arranged on the light emitting side of the condenser lens 43.

The illuminating fiber bundle 41 includes an operating section 101 and an inserting section 10 of the endoscope scope 107 shown in FIG.
3, a heat ray reflection filter for reflecting heat rays emitted from a light source provided in the endoscope body 109, a light quantity adjusting diaphragm for adjusting light quantity, and a condenser lens for collecting light. The light for illumination that has passed through the condenser lens 43
Incident on.

The condenser lens 43 collects the light incident from the illumination fiber bundle 41 at the focal point P, diffuses it, and then enters it into the cone-shaped plano-concave lens 45. Further, the diameter of the condenser lens 43 is substantially the same as the diameter of the illumination fiber bundle 41. Further, the condenser lens 43 is selected such that the focal point P thereof is at the same point as the center of curvature of the concave surface 45a of the cone-shaped concave lens 45, or at a point slightly off the concave surface 45a from the center of curvature.

The cone-shaped plano-concave lens 45 is arranged with its concave surface 45a facing the light emission side of the illumination fiber bundle 41, diffuses the light incident from the illumination fiber bundle 41, and emits it as illumination light. The cone-shaped plano-concave lens 45 has a side surface 47 provided with an inclination with respect to the optical axis. The inclination angle is such that the light rays that are incident on the concave surface 45a from the condenser lens 43, are refracted, and are incident on the inner surface of the side surface portion 47, face the side surface portion 47, and the light exit surface 4 on the side surface portion 47 side.
The angle is such that it reflects toward 5b. Further, the inner surface of the side surface portion 47 is vapor-deposited with a highly light-reflecting metal such as silver or aluminum.

The optical axes of the condenser lens 43 and the cone-shaped plano-concave lens 45 are the same as those of the fiber bundle 4 for illumination.
It is arranged so as to be on the same straight line as the optical axis of 1. next,
The optical characteristics of the condenser lens 43 and the cone-shaped plano-concave lens 45 will be described with reference to FIG. Note that here, of the light rays emitted from the illumination fiber bundle 41,
4 of the light rays R11 and R12 near the optical axis C and the light rays R13 and R14 near the peripheral portion of the illumination fiber bundle 41.
The book will be described as a representative.

As shown in FIG. 4, the light rays R1 and R2 emitted from the illumination fiber bundle 41 are collected by the condenser lens 4
3 and is condensed at the focal point P, then diffused and incident on the concave surface 45a of the cone-shaped plano-concave lens 45, refracted and emitted from the emitting surface 45b as light rays r11 and r12.

On the other hand, the light rays R13 and R14 emitted from the illumination fiber bundle 41 enter the condenser lens 43, are condensed at the focal point P, are diffused, and then are incident on the concave surface 45a of the cone-shaped plano-concave lens 45. Then, it is refracted and hits the inner surface of the side surface portion 47 of the cone-shaped plano-concave lens 45. Here, the side surface portion 47 of the cone-shaped plano-concave lens 45 is the condensing lens 43.
The light rays that are incident on the concave surface 45a, are refracted, and strike the inner surface of the side surface portion 47 are inclined so as to be reflected toward the emission surface 45b on the side surface portion 47 side facing the side surface portion 47. Further, the inner surface of the side surface portion 47 is vapor-deposited with a highly light-reflecting metal such as aluminum. Therefore, the rays R13 and R14
Hits the inner surface of the side surface portion 47 and is reflected toward the emission surface 45b on the side surface portion 47 side facing the side surface portion 47. The reflected light rays R13 and R14 are further refracted at the emission surface 45b, and the angles are increased to form the light ray r13 from the emission surface 45b.
It is emitted as r14. Therefore, the rays r13 and r1
Since 4 is emitted with a sufficient emission angle, it illuminates the peripheral portion of the illumination target that has not been conventionally illuminated.

As described above, since the illumination optical system 40 of the endoscope apparatus of the third embodiment has the condenser lens 43 and the cone-shaped plano-concave lens 45 arranged on the light emitting side of the illumination fiber bundle 41. The light rays emitted from the vicinity of the peripheral portion of the illumination fiber bundle 41, which has been a loss in the related art, can also be used as the illumination light, and it is also possible to illuminate the peripheral portion of the illumination target that has not been conventionally illuminated. .

Further, by selecting the cone-shaped plano-concave lens 45 having different inclination angles of the side surface portion 47, the emission angle of the light beam emitted from the cone-shaped plano-concave lens 45 can be changed.

In the illuminating optical system 40 of the endoscope apparatus of the third embodiment, the condenser lens 43 is arranged on the light emitting side of the illuminating fiber bundle 41, but the first embodiment shown in FIG. Similar to the illumination optical system 10 of the endoscope apparatus of the example, a cone-shaped rod 13 is provided in close contact with the light-emitting surface of the illumination fiber bundle 11, and the cone-shaped rod 13 is illustrated on the emission surface 23 side. The condenser lens 43 and the cone-shaped plano-concave lens 45 shown in FIG. 4 may be arranged. in this case,
Since the diameter of the emission surface 23 of the cone-shaped rod 13 is smaller than the diameter of the light emission surface of the illumination fiber bundle 41,
The diameter of the cone-shaped plano-concave lens 45 can be made smaller than in the case where the cone-shaped rod 13 is not provided. Therefore, the distal end portion 105 of the endoscope is also the cone-shaped rod 1.
The diameter can be reduced as compared with the case where 3 is not provided.

[0050]

As described above, according to the present invention, the optical path conversion means composed of a truncated cone-shaped optical fiber having a light emitting end diameter smaller than the light incident end diameter is closely attached to the light emitting surface of the optical fiber. Since it is provided, it is possible to diffuse and emit the illumination light supplied from the optical fiber,
Therefore, the illumination light can be efficiently diffused and emitted without increasing the diameter of the distal end portion of the endoscope.

Further, by providing a diffusion lens on the light emission side of the light path conversion means, it becomes possible to further diffuse and emit the illumination light. Further, since the plano-concave lens having the side surface inclined and the highly reflective metal vapor-deposited on the side surface is arranged toward the light emitting surface of the optical fiber, the illumination light supplied from the optical fiber is diffused and emitted. Therefore, the illumination light can be efficiently diffused and emitted without increasing the diameter of the distal end portion of the endoscope.

Further, by disposing a condenser lens between the optical fiber and the plano-concave lens, the illumination light is condensed and then diffused and made incident on the plano-concave lens. The illumination light can be efficiently diffused and emitted without increasing the diameter of the portion.

Further, a truncated cone-shaped optical path conversion means having a smaller light emitting end diameter than the light incident end diameter is provided in close contact with the light emitting surface of the optical fiber, and the side surface is inclined and the side surface is inclined. Since the plano-concave lens in which a highly reflective metal is vapor-deposited is arranged toward the light emitting surface of the optical path conversion means, the illumination light supplied from the optical fiber can be diffused and emitted. The illumination light can be efficiently diffused and emitted without increasing the diameter of the distal end portion of the endoscope.

Furthermore, by disposing a condenser lens between the optical path conversion means and the plano-concave lens, the illumination light is condensed and then diffused and made incident on the plano-concave lens. The illumination light can be efficiently diffused and emitted without increasing the diameter of the distal end portion of the scope.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an illumination optical system of an endoscope apparatus which is a first embodiment of the endoscope apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing a cone-shaped rod.

FIG. 3 is a cross-sectional view showing an illumination optical system of an endoscope apparatus which is a second embodiment of the endoscope apparatus according to the present invention.

FIG. 4 is a sectional view showing an illumination optical system of an endoscope apparatus which is a third embodiment of the endoscope apparatus according to the present invention.

FIG. 5 is an explanatory diagram showing an appearance of a medical endoscope apparatus.

FIG. 6 is a sectional view showing a conventional illumination optical system.

FIG. 7 is an explanatory diagram showing a cross section of a fiber bundle for illumination.

FIG. 8 is an explanatory diagram showing optical characteristics of a plano-concave lens.

[Explanation of symbols]

 10, 30, 40 Illumination optical system 11, 31, 41 Illumination fiber bundle 13 Cone-shaped rod 15 Plano-concave lens 17 Core 19 Cladding 21 Incident surface 23 Emission surface 33 Cone-shaped plano-concave lens 35 Side part 43 Condenser lens 45 Cone shape Plano-concave lens 47 side surface

Claims (6)

[Claims] 1. An optical fiber for illumination, which is provided in an endoscope and supplies illumination light to a tip portion of the endoscope, and a light incident surface provided in close contact with a light emitting surface of the optical fiber. An optical path conversion means comprising a truncated cone-shaped optical fiber having a light emission end diameter smaller than the diameter of the portion, and an optical path conversion means. 2. The endoscope apparatus according to claim 1, wherein a diffusing lens is provided on the light exit side of the light path conversion means. 3. An optical fiber for illumination, which is provided in the endoscope and supplies illumination light to a tip portion of the endoscope, and a concave surface facing the light emitting surface of the optical fiber. An endoscopic device comprising: a plano-concave lens that is inclined and has a highly reflective metal vapor-deposited on the side surface. 4. A condenser lens disposed between the optical fiber and the plano-concave lens, and having a focal point at the same point as the center of curvature of the concave surface of the plano-concave lens or at a point slightly concave from the center of curvature. The endoscopic device according to claim 3, wherein 5. An optical fiber for illumination, which is provided in the endoscope and supplies illumination light to a tip portion of the endoscope, and a light incident surface provided in close contact with a light emitting surface of the optical fiber. A light path conversion means composed of a truncated cone-shaped optical fiber having a light emission end diameter smaller than the diameter of the part, and a concave surface is arranged toward the light emission surface of the light path conversion means,
An endoscopic apparatus comprising: a plano-concave lens having a side surface inclined and a highly reflective metal vapor-deposited on the side surface. 6. A light condensing lens disposed between the optical path conversion means and the plano-concave lens, and having a focal point at the same point as the center of curvature of the concave surface of the plano-concave lens or at a point slightly concave from the center of curvature. The endoscope apparatus according to claim 5, wherein a lens is provided.